“…Most of the studies in this regard are small studies which use different doses of allopurinol and it has been shown that the effect of allopurinol on endothelial function and UA lowering in HF is dose dependent and the drug is most useful with high doses or in patients with elevated UA level. 3,4,6,8,12,20 For example, in the OPT-CHF trial, Hare et al reported that treatment with oxypurinol (the active metabolite of allopurinol) was associated with improved clinical status and survival only in moderate to severe HFrEF patients with hyperuricemia (UA>9.5 mg/dL). 8 However, Baldus et al showed intravenous oxypurinol could have positive inotropic effect independent to endogenous release of catecholamines in patients with HFrEF who had normal UA level.…”